The present invention relates to a pressure regulator for gaseous and liquid fluids, and more particularly relates to a pressure regulator of the type having: a main valve arranged between an inlet and an outlet for the fluid, the valve body of which main valve closes or opens the valve to a variable extent in accordance with a control condition: a control pressure space the pressure in which acts on the main valve body and which is connected on the one hand via a choke with the inlet and on the other hand via a control valve with a vent space; a desired-value transmitter as a function of the setting of which a valve body in the control valve is urged with a given force more or less strongly in the closing direction against the pressure prevailing in the control pressure space; and means for detecting and feeding back the actual value of the pressure in the outlet.
The feedback device, which exerts a force dependent on the actual value of the outlet pressure on the body of the main valve, may be a corresponding pressure surface of the body of the main valve which is exposed to the pressure prevailing at the outlet.
A pressure regulator of this kind is known from German Unexamined Application for Patent (Offenlegungsschrift) No. 26 02 844. From German Unexamined Application for Patent (Offenlegungsschrift) No. 25 37 851 there is also known a pressure regulator with merely fixed adjustable desired value, which has pressure spaces subdivided by diaphragms.
Furthermore the invention relates to the use of such a pressure regulator in a pneumatic conveyance device with adjustable conveyance capacity for powdered to granular bulk material, particularly for the spray-coating of articles. Such devices have a pressure regulator in a propellant gas conduit which is connected to the pneumatic bulk-material conveyor device itself, which operates in accordance with the diffuser or Venturi principle. The device, in addition to the propellant-gas inlet also has an inlet for the bulk material, an inlet for control gas and an outlet for the bulk material-gas mixture.
A pneumatic conveyance device of this type is known from German Pat. No. 1 922 889. By that invention better control is to be obtained with a simple control device.